1. Field of the Invention
The present invention relates to a vehicle energy-management device that controls energy consumption of a vehicle including a plurality of different energy sources and, in particular, to a method for dividing a route to plan control on an engine and a motor.
2. Description of the Background Art
The so-called hybrid vehicles, which are powered by a plurality of different energy sources such as fuel energy and electric energy, have various operation modes to suppress the amount of energy consumption. The operation modes of the hybrid vehicle are, for example, the traveling mode in which the vehicle is only powered by the engine, the traveling mode in which the vehicle is only powered by the motor, the traveling mode in which the vehicle is powered by the combination of the engine and the motor, and the mode in which the engine generates electric power and the generated electric power is accumulated and used to drive the motor.
For example, Japanese Patent Application Laid-Open No. 2001-298805 discloses the technique for controlling the engine and the motor of the hybrid vehicle such that the residual quantity of battery is adjusted to the target value while the amount of fuel consumption is minimized. In this technique, the travel route to the destination is divided into a plurality of sections and the state of charge (SOC) of the battery is predicted for each section.
Even if a travel route to the destination is divided into a plurality of sections and a control plan for the hybrid vehicle is prepared based on the predicted value of the amount of energy consumption in each section, changes in the actual traveling conditions cause an error between the predicted value and the actually measured value of the amount of energy consumption. The original control plan becomes inappropriate due to the accumulation of errors during traveling, whereby the control plan needs to be revised (replanned). However, frequent replanning increases the computation loads applied to the controlling device of the hybrid vehicle. In particular, the number of sections increases with increasing distance or travel time to the destination, whereby massive amounts of calculation are required to create the control plan, taking more time to create and replan the control plan.